Stabilizers

ABSTRACT

A marine fin stabilizer for use with a small ship is provided with a plate for attachment to the outside hull of the ship and which carries the fin-tilting mechanism. Fluid pressure conduits extend from the mechanism through the plate to control equipment mounted inside the hull of the ship. The invention avoids the requirement for a fin shaft gland having to be made in the ship&#39;&#39;s hull and for the fin-tilting mechanism to be accommodated inside the hull.

United States Patent [72] Inventors Rogerlidward Gwynn [50] Field114/126 London;

ReferencesCited UNITED STATES PATENTS 1/1961 Fol] 3,172,389 3/1965Michael John Turnham, London; Alexander-Arthur Tann, West Wickhnm, allof, England [21 1 Appl. No. 829,156

[22] Filed May 23, 1969 4s Patented June 22, 1971 W -YE 73 1 AssigneeMuir-head Limited army-Holman & Stem Beckcnhnm, Kent, England [32]Priority May 29, 1968 1 W ABSTRACT: A marine fin stabilizer for use witha small ship is 25,693/68 provided with a plate for attachment to theoutside hull of the ship and which carries the fin-tilting mechanism.Fluid pressure conduits extend from the mechanism through the plate tocontrol equipment mounted inside the hull of the ship. The inventionavoids the requirement for a fin shaft gland having to be made in theships hull and for the tin-tilting mechanism to be accommodated insidethe hull.

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PATENTEU JUH22 I971 SHEET 1 BF 3 INVENTORS'.

ROGER EDWARD GWYNN MICHAEL JOHN TURNHAM ALEXANDER ARTHUR TANN PATENTEUJUN22 l9?! SHEET 2 OF 3 INVENTORSI ROGER EDWARD GWYNN MICHAEL JOHNTURNHAM ALEXANDER ARTHUR TANN PATENT EU JUN22 I971 SHEET 3 UF 3INVENTORSI ROGER EDWARD GWYNN MICHAEL JOHN TURNHAM ALEXANDER ARTHUR TANNSTABILIZERS BACKGROUND OF THE INVENTION Conventional stabilizers use afin integral with a rotatable shaft which passes through a watertightgland in the ship's hull. The inner end of the shaft is connected to atin-tilting mechanism.

The use of fin stabilizers in relatively small vessels such as yachts,fishing vessels and mine-sweepers ranging up to 1500 tons is notnormally considered worthwhile as the cost of the installation inrelation to the advantage gained is relatively high. Moreover, thecompartments occupied by the tin-tilting mechanism inside the hullrepresent a loss of space.

A further disadvantage of the conventional arrangement of stablilizer isthat it does not lend itself to fitting economically to a ship alreadyconstructed. It will be appreciated that extensive major modification tothe ship's hull is normally necessary if it is to be fitted with a finstabilizer and such work can normally only be undertaken in relativelylarge dockyards at a relatively high price.

An object of this invention is the provision of a relatively cheap andrelatively easily fitted fin stabilizer assembly.

SUMMARY OF THE INVENTION In accordance with the broadest aspect of thisinvention a stabilizer fin assembly for fitting to a ships hullcomprises a plate for external attachment to the ship's hull, a shaftextending transversely away from one face of the plate to which it isrigidly fixed, a fin arranged to be rotatably mounted on the shaft bymeans of a water-lubricated bearing, and a controllable fin-tiltingmechanism attached to the plate so that it is carried outside the hullwith the mechanism being operable to control the angle of tilt of thefin on the shaft.

The invention has the advantage that it is able to provide a relativelycheaply constructed fin assembly capable of being fixed externally to aship's hull without the provision of an expensive gland having to beconstructed in the ship's hull to accommodate a fin-tilting shaft, andwithout the requirement for bulky fin-tilting mechanisms to be mountedwithin the ships hull. The assembly can be fitted to a relatively smallvessel, such as a yacht, at a relatively low price and without majorstructural alteration to the hull of the vessel.

In the preferred arrangement, the shaft comprises a steel rod welded toone face of the plate and cemented inside a cylindrical tube of amaterial such as that known under the Registered Trade Mark Tufnol"which provides one surface of the water-lubricated bearing. The fin mayalso be provided with an integral Tufnol" sleeve which is a sliding fitover the shaft tube so that a water-lubricated bearing is providedthere.

The outer end of the shaft tube beyond the end of the metal rod may beplugged by a spigot which is cemented to the rod with a suitableadhesive, such as that known under the Registered Trade Mark Araldite"which may also be used to cement the Tufnol" tube to the rod. The end ofthe spigot may be externally threaded in order to receive a nut forholding the fin in place on the shaft.

The rotation of the fin about the shafi axis is suitably carried out bya member encircling the shaft and arcuately movable by the tiltingmechanism. The movement of the member is conveniently imparted to theadjacent and face of the tin by a pin and socket or other form ofreadily disconnectable attachment.

The fin-tilting mechanism suitably includes a double-ended pistonmounted on the plate within a mask which protects the fin-tiltingmechanism from impact with floating objects.

The working fluid applied to the cylinder is preferably pneumatic ratherthan hydraulic and it is transmitted to the fin assembly by way oftubing extending to a suitable control system which may be of the formdescribed in our copending application Ser. No. 827,278 filed May 23,1969, hereby inserted by way of reference. The pneumatic path providedby the tubing preferably passes through the ships hull beneath the plateby way of a fixture. The tubing may, if required, be cleated to theoutside of the ship's hull and arranged to extend upwardly from theplate to a position above the waterline where it can be led inboard tothe control unit.

The invention will now be described in more detail, by way of example,with reference to the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view, partly insection, of a fin stabilizer assembly;

FIG. 2 is a vertical section taken on the line and in the directionindicated by the arrows ll-II in FIG. 1; and,

FIG. 3 is a view of the fin-tilting mechanism shown in FIG. 1 and takenin the direction of the arrow A, with the fin and mask having beenremoved.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 3 the finstabilizer assembly comprises a generally flat plate 1 having bolt holes2 formed therein and made of mild steel treated so as to be resistant tosea water corrosion. Welded to the plate I is one end of a cylindricalsteel rod 3 (FIG. 2) whose other end is cemented into the bore of a tube4 made of material such as that known under the Registered Trade MarkTufnol." Cemented into the outer end of the tube 4 is a nylon plug 5externally threaded at 6 to receive a lock nut 7. The nut 7 holds inplace on the outside of the tube 4 a stabilizing fin 8.

Welded to the plate 1 about the rod 3 is a steel strengthening collar10. This collar abuts the inner end of the tube 4 and provides acylindrical surface which is cemented into the bore of a Tufnol" ring11. The outer surface of the ring 11 and the adjacent portion of thetube 4 provide a water-lubricated bearing for a partially rotatablecross-head 12 constructed as a one-piece moulding of Tufnol." A flange14 on the collar 10 holds the cross-head 12 away from the surface of theplate 1. A pair of corrosion-resistant drive pins 15 are cemented intorespective holes in the crosshead 14 so that their outer ends 16 locatein cups I7 which are integrally formed in the adjacent end face of thefin 8.

The crosshead 12 is of generally rectangular form as shown in FIG. 3 andis provided with slotlike recesses 46 across each of which extends arotatable pin 47 to which is clamped by a bolt 18 an endpiece 20. Eachendpiece has screwed therein one threaded end 21 of a piston rod 22which extends to a double-ended piston reciprocable inside a cylinder23.

The two piston and cylinder units provide with the crosshead 12 afin-tilting mechanism. Working chambers in opposite ends of each of thecylinders 23 are connected by connectors 24 to flexible nylon piping 25so arranged that the admission of pressure fluid through one of the twoconnectors 24 is accompanied by the admission of pressure fluid to thesecond connector 24' of the other cylinder 23. Further nylon tubing 26and 27 extends from connectors 24 of respective cylinders to fixtures 28provided in the plate 1 and from which skin fittings project through thehull of the ship. Skin fittings are well known in the marine art forconveying pressure fluid through a ship's hull and they are thereforenot shown. The inner ends of the skin fittings are connected by furtherpiping inside the ship's hull to a suitably positioned control unit foradjusting air pressure admitted by way of the tubing to the cylinders 23of the fin-tilting mechanisms. The control unit is preferablyconstructed as described in our above-mentioned copending Application.

The cylinders 23 have end lugs 30 rotatably mounted on pivot pins 31welded to the plate 1. A pair of pillars 32, 32

also welded to the plate l as shown in FIG. 1 have threaded ends ontowhich are screwed nuts 33 which hold in place a fiberglass molded mask1% covering the fin tilting mechanism. The pillar 32 has mounted thereona rubber ring 36 providing a buffer to limit resiliently rotary movementof the crosshead 12 to an angle of thirty degrees from the positionshown in FIG. 3.

The construction of the fin will now be described.

The fin 8 is of symmetrical aerofoil cross section and its leading edgetapers slightly rearwardly towards its outside face.

Referring to FIG. 1, the fin is provided with a skeleton frame formed bya pair of steel ribs 40, 41 disposed, respectively, adjacent the innerand outer ends of the fin and held in place by a pair of tiebars 42, 453disposed towards the leading and trailing edges of the fin. A sleeve 44made of the aforementioned Tufnol" has an internal diameter slightlylarger than the external diameter of the tube 4 of the shaft whichextends through .the thickest part of the tin 8 between the ribs 40, 41.The frame and sleeve are fitted into a premolded fiberglass sheathproviding the outside surface of the fin and the cavity of the fin isthen filled with foamed polyurethane which is solidified in situ toprovide a rigid and light filling to the sheath. Molded in situ in thepolyurethane are the two cups 17 which receive the ends 16 of the pins15 with a close fit.

The outer end face of the fin is provided with a counterbored recess 51coaxially arranged with respect to the sleeve 44 and disposed outwardlyof the rib 41 as shown in FIG. 1. The nut 7 which locks the fin to theshaft is largely accommodated within the recess 51. A screw 52 clampsthe nut 7 in position as shown in FIG. 2. y

The above described assembly is duplicated on both sides of the ship andmay be comparatively cheaply fabricated as well as being relatively easyto assemble and transport. Moreover it is relatively light.

To fit the fin assembly to the hull of the ship the plate 1 is bolted tothe hull at the position required and the skin fittings are made atappropriate positions for connection through the plate 1 to the tubing26 and 27. The tubing 26, 27 is then connected and the protective mask 3is bolted to the pillars 32. Finally the fin is threaded onto the shaftwhich projects from the mask 34 and the protruding ends 116 of the pins15 are located within the cups 117 of the fin.

The nut 7 is finally screwed onto the plug and the bolt 52 inserted toclamp it in position.

To operate the fin assembly compressed air is admitted selectively tothe piping 26, 27 while the other piping is simultaneously connected toatmosphere. The two piston and cylinder units are therefore operated inunison in respectively opposite directions to rotate the crosshead l2and thus, by way of the pins 15, the fin We claim:

11. A marine stabilizer fin assembly comprising a ships hull, a plateexternally attached to the ship's hull, a shaft extending transverselyaway from one face of the plate to which it is rigidly attached, a finrotatably mounted on said shaft, a water-lubricated bearing supportingsaid fin on said shaft, a

fin-tilting mechanism attached to the outside of the plate, saidmechanism comprising a member rotatable about said shaft, a secondwater-lubricated bearing between said member and said shaft, a fluidpressure operated arrangement connected between said member and saidplate and expandable to rotate said member about said shaft, andquick-release connections between said member and said fin, and meansextending from said mechanism to a tilt control unit mounted inside theship.

2. The assembly as set forth in claim 1, in which said arrangementcomprises two piston and cylinder units connected at one pair ofrespective ends to positions on said member on opposite sides of saidshaft and at the other pair of respective ends to said plate, and saidquick-release connections comprise pin and socket elements attachedrespectively to said member and to said fin.

3. A stabilizer fin assembly comprising a plate attached to a ships hullbeneath the waterline, a steel rod welded to said plate, a tube ofwater-lubricated material cemented around a part of said rod, a plugcemented into the outer end of said 5 tube, a threaded end-portion tosaid plug, a fin having a bore threaded onto said tube, a lining ofwater-lubricated material to said bore, a recess in the outer end ofsaid bore, a nut located in said recess and screwed onto said threadedend-portion of said plug, a mask fixed to said plate and defining anaperture around said shaft, a fin-tilting mechanism mounted within saidmask, control connections extending to said mechanism from said plate,and means converting movement of said mechanism into tilting movement ofsaid fin about said shaft.

4. The assembly as set forth in claim 3, in which said means andmechanism include a member threaded onto said shaft and located insidesaid mask, a water-lubricated bearing formed between said member andsaid shaft, dowel pins fixed in said member and 5 protruding towardssaid fin, cups formed in said fin and receiving end-portions of saiddowel pins, fluidpressure expansion means connecting said member to saidplate, and piping providing said connections between said plate and saidexpansion means of said fin-tilting mechanism.

5. The assembly as set forth in claim 4, in which said fluidpressureexpansion means comprise two double-endedpiston and cylinder unitsextending to pivotal connections on said member at opposite sides ofsaid shaft.

6. The assembly as set forth in claim 3, in which the fin is of moldednylon.

7. The assembly as set forth in claim 3, in which the tin comprises afiberglass sheath containing a solidified filling of polyurethane, ametal frame embedded in said solidified filling, a tube ofwater-lubricated material embedded in said 5 filling and providing withsaid shaft a water-lubricated bearing, and parts of spigot-and-socketconnections connecting said fin to said tilting mechanism.

8. The assembly as set forth in claim 3 in which fixtures passingthrough said plate are connected by flexible piping to said fin-tiltingmechanism whereby tilting of said fin is determined by the fluidpressure selectively applied to said piping from a control unit mountedwithin the ship's hull and connected by further piping to said fixtures.

1. A marine stabilizer fin assembly comprising a ship''s hull, a plateexternally attached to the ship''s hull, a shaft extending transverselyaway from one face of the plate to which it is rigidly attached, a finrotatably mounted on said shaft, a waterlubricated bearing supportingsaid fin on said shaft, a fintilting mechanism attached to the outsideof the plate, said mechanism comprising a member rotatable about saidshaft, a second water-lubricated bearing between said member and saidshaft, a fluid pressure operated arrangement connected between saidmember and said plate and expandable to rotate said member about saidshaft, and quick-release connections between said member and said fin,and means extending from said mechanism to a tilt control unit mountedinside the ship.
 2. The assembly as set forth in claim 1, in which saidarrangement comprises two piston and cylinder units connected at onepair of respective ends to positions on said member on opposite sides ofsaid shaft and at the other pair of respective ends to said plate, andsaid quick-release connections comprise pin and socket elements attachedrespectively to said member and to said fin.
 3. A stabilizer finassembly comprising a plate attached to a ship''s hull beneath thewaterline, a steel rod welded to said plate, a tube of water-lubricatedmaterial cemented around a part of said rod, a plug cemented into theouter end of said 5 tube, a threaded end-portion to said plug, a finhaving a bore threaded onto said tube, a lining of water-lubricatedmaterial to said bore, a recess in the outer end of said bore, a nutlocated in said recess and screwed onto said threaded end-portion ofsaid plug, a mask fixed to said plate and defining an aperture aroundsaid shaft, a fin-tilting mechanism mounted within said mask, controlconnections extending to said mechanism from said plate, and meansconverting movement of said mechanism into tilting movement of said finabout said shaft.
 4. The assembly as set forth in claim 3, in which saidmeans and mechanism include a member threaded onto said shaft andlocated inside said mask, a water-lubricated bearing formed between saidmember and said shaft, dowel pins fixed in said member and 5 protrudingtowards said fin, cups formed in said fin and receiving end-portions ofsaid dowel pins, fluid-pressure expansion means connecting said memberto said plate, and piping providing said connections between said plateand said expansion means of said fin-tilting mechanism.
 5. The assemblyas set forth in claim 4, in which said fluid-pressure expansion meanscomprise two double-ended piston and cylinder units extending to pivotalconnections on said member at opposite sides of said shaft.
 6. Theassembly as set forth in claim 3, in which the fin is of molded nylon.7. The assembly as set forth in claim 3, in which the fin comprises afiberglass sheath containing a solidified filling of polyurethane, ametal frame embedded in said solidified filling, a tube ofwater-lubricated material embedded in said 5 filling and providing withsaid shaft a water-lubricated bearing, and parts of spigot-and-socketconnections connecting said fin to said tilting mechanism.
 8. Theassembly as set forth in claim 3 in which fixtures passing through saidplate are connected by flexible piping to said fin-tilting mechanismwhereby tilting of said fin is determined by the fluid pressureselectively applied to said piping from a control unit mounted withinthe ship''s hull and connected by further piping to said fixtures.